Fix the include guard of revstr.hpp

src/utils/revstr.hpp

@@ -1,5 +1,5 @@
-#ifndef REVSTRP_INCLUDED
+#ifndef REVSTR_HPP_INCLUDED
-# define REVSTR_INCLUDED
+# define REVSTR_HPP_INCLUDED
 
 #include <string>
 
@@ -8,4 +8,4 @@ namespace utils
   std::string revstr(const std::string& original);
 }
 
-#endif // REVSTR_INCLUDED
+#endif // REVSTR_HPP_INCLUDED